Electric hospital bed

ABSTRACT

Electric hospital bed with articulated spring having Hi-Lo, head and knee function drive means with respective manually operable control members selectively movable from neutral in either of two directions and a normally neutral control unit operable in response to each control member first to move a gear selector to effect driving connection for the selected bed function and thereafter to close one or the other of two switches to initiate motor operation for either up or down bed function movements, with means operable automatically upon release of an actuated head or knee control member to return the parts manually operated thereby to neutral position and &#39;&#39;&#39;&#39;NO-WAIT&#39;&#39;&#39;&#39; means for latching the Hi-Lo control member and parts manually actuated thereby in operative position following manual actuation and release and automatically operable in response to movement of the bed into its highest or lowest positions to return the Hi-Lo member and mechanisms actuated thereby to neutral positions, and simplified lockout means for selectively preventing operation of the head or knee control members, together with simplified Trendelenberg control means.

United States Patent n91 Peterson 1 Jan. 16,1973

[54] ELECTRIC HOSPITAL BED [75] lnventor: Warren J. Peterson, Two Rivers,

Wis.

[73] Assignee: Joerns Furniture Company, Stevens Point, Wis.

[22] Filed: April 15, 1971 [21] Appl. No.: 134,197

[52] US. Cl. ..5/68, 5/63 [51] Int. Cl. ..A6lg 7/00, A61g 7/10 [58] Field of Search ..5/63, 66-69 [56] References Cited UNITED STATES PATENTS 3,414,913 12/1968 Stanley et al 5 /68 3,216,026 11/1965 Mann v ..5/66 3,581,319 6/1971 Stanley et a1 ..5/68

Primary ExaminerCasmir A. Nunberg Attorney-Davis, Lucas, Brewer & Brugman [57] ABSTRACT Electric hospital bed with articulated spring having Hi- Lo, head and knee function drive means with respective manually operable control members selectively movable from neutral in either of two directions and a normally neutral control unit operable in response to each control member first to move a gear selector to effect driving connection for the selected bed function and thereafter to close one or the other of two switches to initiate motor operation for either up or down bed function movements, with means operable automatically upon release of an actuated head or knee control member to return the parts manually operated thereby to neutral position and NO-WAIT means for latching the Hi-Lo control member and parts manually actuated thereby in operative position following manual actuation and release and automatically operable in response to movement of the bed into its highest or lowest positions to return the Hi-Lo member and mechanisms actuated thereby to neutral positions, and simplified lockout means for selectively preventing operation of the head or knee control members, together with simplified Trendelenberg control means.

14 Claims, 6 Drawing Figures gmqu A r wm hm Pf. I? 1 .21.? my} wi i SHEET 3 [IF 4 q m um PATENTEDJAH 16 I973 PATENTED JAN 16 M5 SHEET U [1F 4 ELECTRIC HOSPITAL BED DESCRIPTION OF THE PRIOR ART Hospital beds with an articulated spring and means for selectively moving the same up and down and for independently raising and lowering the head and knee sections of the spring by means of an electric motor are well known. In some of the prior structures, various types of clutches were interposed between the electric motor and the driving mechanisms operable thereby to perform the desired functions selectively. The means for controlling the operations of the several actuating means by the motor were positioned for convenient operation by a patient on the bed. With use of selectively operable clutches, such control means, as for example in U. 8. Pat. No. 2,913,300, comprised three separate members each selectively operable from a normal neutral position in either of two directions to mechanically engage one clutch for Hi-Lo, head or knee operation and simultaneously to energize the reversible motor for a raising or lowering in accordance with the direction of movement manually applied to the selected control member. A generally similar arrangement is disclosed in U. S. Pat. No. 2,912,704 in which electrically operated clutches are substituted for the mechanical clutches, and U.S. Pat. No. 3,198,891 which substitutes a pair of single pole, single throw switches operable by any one of three shuttle bars to determine the direction of rotation of the motor in response to manual movement of an associated control member which simultaneously operates the associated one of three mechanical clutches.

To eliminate such clutches, which comprise portions of those structures most susceptible to wear, gearing with selectively movable transmission means was incorporated in such electrically operable hospital beds. U. S. Pat. No. 3,414,913 discloses such a bed structure and application Ser. No. 813,647, filed Apr. 4, 1969, now issued as U. S. Pat. No. 3,581,319 discloses a simplification thereof using the same type of selectively operable transmission with a chain and sprocket arrangement substituted for some of the more expensive gears. With this type of drive mechanism, it was found desirable to provide a manually operable member selectively movable to any one of three positions to effect power transmission from the single electric motor to the desired one of three separate actuating means, and a separate manually operable control member to determine the direction of rotation of the motor. Such use of selectively positionable gear transmission means instead of clutches resulted in more positive driving as well as the elimination of the clutch parts most susceptible to wear. However, it constituted the initially most expensive construction, especially if the selection or shifting of the gear transmission means was designed to take place after or substantially simultaneously with the starting of the motor in orderto avoid use of a larger or more expensive motor. Thus, the use of separate control members for selecting the desired function and for causing energization of the motor required interlocks and careful attention on the part of the nurse or patient operating the bed, first, to select the desired one of the three available functions and, second, to initiate operation of the motor in the desired direction. Without careful conscious attention, improper bed actuation could result which, at best, is

disconcerting and, in some circumstances, may present a hazard to the patient.

SUMMARY OF THE INVENTION Such difficulties have been overcome by the instant invention which, while employing gear selector mechanism instead of clutches, provides a single manually operable member for each of the three functions (Hi-Lo, head and knee) and means operable thereby for first effecting the desired selection and gear transmission shifting and thereafter energizing the motor in the proper direction, all in one motion of the operator. To this end, the invention comprises a novel control unit assuring such desired sequential operation of the transmission means and energization of the motor. More specifically, the control unit comprises a gear selector in the form of a shuttleplate slidable to one of three positions in response, respectively, to pivotal movements of three function selector arms in either clockwise or counterclockwise directions. The function selector arms are pivotally moved by associated control members which may be manually operated selectively from a normal or at rest position in either of two directions. During the final portion of movement of any one of the selector arms, it will actuate a switch bar to close one or the other of two switches to energize the motor for forward or reverse directional rotation.

The invention further assures immediate return of the manually operable head or knee section function controls and their related members to an exact neutral position upon manual release thereof. In addition, it incorporates a NO-WAIT holding or latching arrange: ment automatically effective upon selective movement of the manually operable control. member for Hi-Lo operation to retain that control member in operated position when it is manually released and to effect sub sequent return thereof to an exact center or neutral position when the bed reaches its uppermost or lowermost position. This is of particular importance in saving the nurses time, since it permits her to go about other business while the up or down bed movement continues. At the same time, the Hi-Lo control member is positioned out of the field of reach of the patient in the bed.

The invention further includes simplified means for effecting positioning of the bed spring in Trendelenberg or reverse Trendelenberg positions which includes normally inoperative detents and manually operable control means for rendering the same effective when the bed is in its uppermost position. Thereafter, movement of the Hi-Lo control member to initiate lowering of the bed and its release will result in automatic lowering and stopping of the other end of the bed in its lowermost position by virtue of the NO-WAIT" holding mechanism.

lnterlocks for preventing patient-initiating control of selected bed functions are known, but the control means of thisinvention are so designed as to enable the use of extremely simple lockout means which materially reduces the cost of incorporating the same in the bed structure.

In the drawings:

FIG. 1 is a plan view, with parts broken away for clarity, of a hospital bed embodying the features of the invention;

FIG. 2 is a detail plan view similar to FIG. 1 showing the control unit on a larger scale;

FIG. 3 is a side elevation of the control unit as seen from the lower side of FIGS. 1 and 2;

FIG. 4 is a transverse section, with parts omitted, taken substantially on the line 4--4 of FIG. 2;

FIG. 5 is an exploded perspective view of the control members at the foot end of the bed; and

FIG. 6 is a detail elevation of a part of the Trendelenberg mechanism.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring more particularly to FIG. 1, an electric bed embodying the features of the invention is illustrated as comprising a main frame, indicated generally by reference numeral 11, which is supported at each end in well-known manner by means of four outer legs 12 secured thereto and telescopically engaging inner floor-supported legs 13 (FIGS. 5 and 6). The main frame 11 supports a normally horizontally disposed, articulated spring which comprises an intermediate or seat section 14 rigidly secured to the frame, a head section 15 pivotally connected to the intermediate section at 16, a knee section 17 pivoted to the seat section 14 at 18, and a foot section 19 pivotally connected at 21 to the knee section 17. The frame 11 includes side rails 22, and a plurality of rigid transverse members including outer and inner gear box plates 23 and 24 and a bearing frame plate 25.

Hi-Lo drive means are provided for raising and lowering the frame 11 and the articulated spring mounted thereon relative to the floor-supported inner legs 13 which are similar to those of Ser. No. 813,647, filed Apr. 4, 1969, now issued as U. S. Pat. No. 3,581,319, and including a Hi-Lo screw 26 mounted in suitable thrust bearings carried by the inner gear box plate 24 and the frame plate 25 which is engaged by a nut thereon constrained in well-known manner against rotation and slidably mounted for longitudinal movement relative to the frame 11. Secured to that nut are the ends of two pairs of cables 27 and 28, the former of which extend toward the head of the bed (to the right in FIG. 1) around suitable guide sheaves 29 and 31 and are secured to the upper ends of the lower or inner legs 13. The other cables 28 extend forwardly to and around guide sheaves 32 and rearwardly therefrom (to the left in FIG. 1) and over similar guide sheaves 29 and 31 for attachment to the upper ends of the inner legs 13. Consequently, rotation of the Hi-Lo screw 26 results in raising or lowering of the frame 11 and the articulated spring relative to the inner supporting legs 13, depending upon the direction of that screw rotation.

Head section drive means also are provided for raising and lowering the head section 15 of the spring about its pivots 16 relative to the frame 11 which include a head screw 33 mounted in the frame plates 24 and 25 in similar manner to the Hi-Lo screw 26, a nut 34 threadedly engaging the screw, and forwardly ex tending links 35 connected at their rear ends to the screw 33. The forward ends of links 35 are pivotally connected to crank arm means 36 secured to a transverse crank shaft 37. With this arrangement, rotation of the screw 33 will cause translation of the nut 34 and the links 35 connected thereto to rotate the crank shaft 37 through the agency of the crank arm means 36 to swing the head section 15 up or down about its pivots 16 depending upon the direction of rotation of the head screw 33.

Knee section drive means of similar construction also are provided for raising and lowering the knee section 17 about its pivots 18 relative to the frame 11 which include a knee screw 38 mounted in similar manner to the screws 26, 33, a nut mounted thereon similarly to nut 34 on the screw 33 and forwardly extending links 39 connected at their rear ends to that nut. The forward end portions of these links 39 are pivotally connected to crank arm means 41 secured to a transverse crank shaft 42 depending from the inner end portion of the knee section 17. Rotation of the knee screw 38 thus will be transmitted by means of the nut-thereon, links 39, crank arm means 41 and crank shaft 42 to the knee section 17 to swing the same up or down about its pivots 18 depending upon the direction of rotation of the screw 38. These Hi-Lo, head and knee section drive means are arranged and operate similarly to the comparable parts disclosed in U. S. Pat. Nos. 3,281,873 and 3,581,319.

As in the latter, the three drive screws. 26, 33 and 38 are adapted to be selectively actuated by a reversibly operable electric motor 43 through the agency of transmission means mounted between the plates 23 and 24. This transmission means includes sprocket wheels secured to the outer ends of shafts comprising extensions of screws 26 and 33 which are driven, respectively by chains 44 and 45. These chains are driven by sprocket wheels which are mounted coaxially with a gear 46 which, in turn, meshes with a gear 47 secured to an outer extension of the knee screw 38. This transmission means also includes a drive key slidably disposed interiorly of the sprocket wheels for driving the chains 44 and 45 and the coaxially mounted gear 46, which key is selectively positionable axially of those sprocket wheels and the gear 46 to drivingly engage one of them, as illustrated in FIG. 2 of US. Pat. No. 3,581,319. A carrier 48 for this key is rotatably secured at its rear end, as shown herein in FIG. 2, to a depending arm or yoke portion of a shift plate 49, the latter normally being in its neutral position of FIG. 2 in which the drive key of the transmission means is positioned in engagement with the sprocket wheel driving the chain 44. Consequently, energization of the motor 43 when the drive key of the transmission means is so positioned will result in rotation of the Hi-Lo screw 26 through the agency of the chain 44. Selective movement of the carrier 48 by the shift plate 49 to the right in FIG. 2 will position the drive key in operative engagement with the gear 46 to result in rotation of the knee screw 38 when the motor is energized, whereas movement of the shift plate 49 and carrier 48 to the left from its normal neutral position of FIG. 2 will drivingly engage that key with the outermost sprocket wheel for actuating the chain 45 to rotate the head screw 33 when the motor is energized.

Operation of the reversible motor 43 is controlled as in US. Pat. No. 3,581,319 by a pair of microswitches 51 and 52 (FIGS. 2 and 3) having upwardly extending operating members 53 and 54, respectively, which may be selectively actuated by longitudinal movement of a switch bar 55 having a depending outer end positioned therebetween. Thus, movement to the left in FIG. 3 of the switch bar 55 from its illustrated normal neutral position will engage its depending end with the operating member 53 to close microswitch 51 to energize the motor for rotation in one direction for down" movement of the selected bed function, while movement of the switch bar 55 to the right from its position of FIG. 3 will cause its depending end portion to engage the operating member 54 to close the microswitch 52 to effect reverse rotation of motor 43 for up" movements.

This invention includes a normally neutral control unit, indicated generally by reference numeral 56, and the shift plate 49 and switch bar 55 comprise part of, and are selectively operable by, that control unit. As best seen in FIG. 2, the control unit 56 includes a horizontal shuttle plate 57 mounted for sliding movement on a longitudinally extending supporting member 58 which is carried by the laterally extending frame plates 24 and 25. Upstanding from the supporting member 58 are three stationary pins 59 which are spaced longitudinally of the bed from each other and slidably cooperate with suitable slots 61 in the shuttle plate 57. The pins 59 and slots 61 guide the longitudinal sliding movements of the shuttle plate 57. As best seen in FIGS. 2 and 4, the lateral edge portions of the shuttle plate 57 are provided with upstanding ribs 62, and the central portion of the shuttle plate 57 is formed with apertures 63 extending therethrough.

The control unit 56 also comprises three selectively operable arms for slidably positioning the shuttle plate 57. One of these is a head arm 64 which is pivotally mounted on the inner stationary pin 59 (the rightmost in FIG. 2) and, as shown in FIG. 3, rests upon the upper surface of the inner marginal end portion of the shuttle plate 57. The upper end of the head rod 64 (as viewed in FIG. 2) is pivotally connected to the inner end of a rod 65, the outer end of which is adjustably and pivotally connected, as seen in FIGS. 1 and 5, to one arm of a bell crank or manually operable control member 66 which is pivotally mounted on a stationary pin 67. The other arm of the control member 66 extends outwardly as shown in FIG. 5 through a slot defined by an inwardly and downwardly bent portion 68 of an end cover plate 69 secured in any suitable manner to the foot end of the bed frame. The bell crank 66 thus comprises a manual control member selectively operable to pivotally move the head arm 64 on its pivot 59 in either direction through the agency of the head rod 65.

The other end of the head arm 64, which is at the bottom of FIG. 2, is pivotally and adjustably connected to the outer end of an auxiliary or duplicate head rod 71, the inner end of which is pivotally connected, as seen in FIG. 1, to one end of a pivotally mounted bell crank 72. The other end of the bell crank 72 is secured in well-known manner to a head shift tube 73 which is rotatably mounted at its ends and extends through vertical side plates 74 on the seat section 14. Outward of these side plates, each end of the tube 73 is secured to the lower end of a handle 75, each of which handles comprises a duplicate head control member selectively manually operable from its neutral position of FIG. 1 in either of two directions by a patient on the bed. Such movements of the head control member 75 will be imparted to the head arm 64 in the same manner and to the same effect as obtains with respect to the head control member 66 at the foot of the bed.

Regardless of whether the head arm 64 is thus swung in a clockwise or counterclockwise direction about its stationary pivot 59, its outer or leftmost edge, as seen from above in FIG. 2, will abut against the adjacent end of one or the other of the upstanding ribs 62 to move the shuttle plate 57 outwardly or to the left in FIG. 2 a predetermined distance. Since the shift plate 49 is secured to the shuttle plate 57, as by means of bolts 76, such outward movement of the shuttle plate by the head arm 64 will move the drive key of the transmission means from its normal engagement with the sprocket wheel that drives the chain 44 into driving engagement with the outer sprocket wheel which engages the chain 45 to drive the head screw 33.

For selectively positioning the: transmission means for knee section operation, the control unit 56 includes a knee arm 77 which is pivotally mounted on the outer or leftmost stationary pin 59, as seen in FIG. 2. Like its counterpart, the head arm 64, this knee arm 77 overlies the shuttle plate 57 and is connected pivotally at one end (the lower end in FIG. 2) to the inner end of a knee rod 78. As seen in FIGS. 1 and 5, the outer end of the knee rod 78 is adjustably and pivotally connected to one arm of a manually operable knee control member 79 in the form of a bell crank pivotally mounted on a stationary pin 81. As in the case of the head control member 66, the other arm of the knee control member 79 extends outwardly for manual operation through the slot provided by the bent portion 68 of the end cover plate 69.

Referring back to FIG. 2, the upper end of the knee arm 77 is pivotally and adjustably connected to the outer end of an auxiliary or duplicate knee rod 82, it being understood that these pivotal and adjustable connections between the arm 77 and rod 82 and the rod 78 and bell crank control member 79, like those between the members 64 and 71 and 65 and 66, are of wellknown construction which permit of longitudinal adjustment of the rods 65, 71, 78 and 82 to assure proper operation of the control unit 56. Referring to FIG. 1, the other or inner end of the duplicate knee rod 82 is pivotally connected to one arm of a bell crank 83, the other arm of which is rigidly connected to a knee shift tube 84. As in the case of the head shift tube 73, the knee shift tube 84 is rotatably supported adjacent its ends and extends outwardly through the vertical side plates 74 of the seat section 14. Suitable handle means 85 comprising duplicate knee control members are secured at their lower ends to the shift tube 84 and are disposed so that the upper ends thereof may be selectively moved in either of two directions from their normal neutral positions by a patient on the bed.

Manual operation of either the knee control member 79 at the foot of the bed or one ofthe duplicate control members 85 at the lateral ends of the seat section 14 will correspondingly swing the knee arm 77 either clockwise or counterclockwise from its normal neutral position of FIG. 2. In the event of either such movement of the knee arm 77, the inner edge thereof will abut against the adjacent outer end of one or the other of the upstanding ribs 62 to move the shuttle plate 57 a predetermined distance inwardly or to the right in FIG. 2. This will selectively position the key drive of the transmission means in its innermost or righthand position in operative engagement with the gear 46 for establishing a driving connection between the motor 43 and the knee screw 38.

A third function selector arm forms a part of the control unit 56 which comprises a Hi-Lo arm 86 pivotally mounted intermediate its ends on the central stationary pin 59 and overlying the central portion of the shuttle plate 57. One end of this arm 86, the lower end as seen in FIGS. 1 and 2, is pivotally connected to the inner end of a l-li-Lo rod 87, the outer end of which is pivotally and adjustably connected to one arm of a bell crank 88 (FIG. comprising a manually operable Hi-Lo control member which is pivotally mounted on a stationary pin 89. The other arm of this bell crank 88 extends outwardly through the slot provided by the bent portion 68 of the end cover plate 69 for selective manual operation from a point adjacent the foot of the bed.

Depending from the Hi-Lo arm 86 adjacent the ends thereof are two pins or studs 91 which are spaced equally from the stationary pivot pin 59 and extend downwardly through the apertures 63 in the shuttle plate 57. These depending studs 91 thus cooperate with the ends of the slots 63 to centrally position the shuttle plate 57, regardless of the direction of pivotal movement of the arm 86, to assure driving engagement of the drive key of the transmission means with the sprocket wheel engaging the chain 44 to cause rotation of the Hi-Lo screw 26 in response to energization of the motor 43. Since it is preferred that the bed patient not be able to effect raising and lowering of the bed frame, the manually operable control 88 for Hi-Lo function selection is disposed only at the foot end of the bed.

As indicated, operation of the Hi-Lo control member 88 assures central positioning of the shuttle plate 57 in its normal neutral position of FIG. 2. The control unit 56 also includes means automatically operable to return the head or knee function selector control members 66, 71 and 79, 85 and the parts actuated in response to manual operation thereof back to normal or neutral position upon manual release of the selectively operated control member. This centering means for returning the manually operated parts to normal neutral position comprises a pair of followers 92 adjacent the longitudinal ends of the shuttle plate 57 which are interconnected by a coil spring 93 (FIGS. 1 and 3). Each of these followers 92 has an inner portion overlying the associated arm 64 or 77 with a movement-limiting slot 94 therein cooperating with the associated stationary pin 59. Each of the followers 92 also has a central portion defining a vertical rib 95 engaging the outer edge of the associated arm 64 or 77 (FIG. 3), and an outer portion that comprises a tongue 96 slidable in a groove 97 in the supporting member 58 and laterally extending flanges 98 disposed under the upper portion of the supporting member 58. With this arrangement, pivotal movement of either of the arms 64 or 77 will result in corresponding movement of the associated follower 92 against the action of the spring 93, and manual release of the control member which was actuated to effect such arm pivoting will result in the spring 93, through the agency of the followers 92, returning the actuated arm 64 or 77 and the parts moved thereby to normal neutral positions.

From the above description, it will be observed that manual operation of any one of the function control members 66 or 71, 79 or 85, or 88 will pivotally move its associated head arm 64, knee arm 77 or Hi-Lo arm 5 86 to slide the shuttle plate 57 as described to effect selective positioning of the drive key of the transmission means. One of the features of the instant invention comprises the subsequent closing of the switch means 51, 52 in response to any such manual operation of one of the control members in order to effect rotation of the motor 43 in the desired direction after the drive key of the transmission means has been initially engaged with the selected driven member. This sequence of operation of first effecting a driving relationship for the desired bed function and thereafter initiating energization of the motor is accomplished by each of the function arms 64, 77 and 86. To this end, each of the function selector arms 64 and 77 is provided with a pin or stud 99 (FIGS. 2 and 3) depending therefrom and spaced from their stationary pivot pins 59 the same distance as the lower stud 91 (as seen in FIG. 2) which depends from the Hi-Lo function selector arm 86. These three studs 91, 99 are disposed substantially along the center line of the switch bar 55 and extend downwardly through corresponding longitudinal slots 101 in that bar.

Consequently, clockwise rotation of any one of the function control arms 64, 77 or 86 will move the switch bar 55 toward the foot of the bed or to the left in FIG. 2 near the end of such movement of the selector arm to engage the depending portion on the outer end of the bar 55 with the operating member 53 to close the microswitch 51. The switches 51, 52 are so connected electrically with the motor 43 that this closing of the switch 51 will energize the motor for rotation to effect lowering of the bed or the head or knee sections of the spring, depending upon which of the function selector arms has been moved clockwise. Similarly, counterclockwise rotation of any of the function selector arms 64, 77 or 86 will result in movement of the switch bar 55 toward the head of the bed or to the right in FIGS. 2 and 3 near the end of the selector arm operation to close the microswitch 52 which effects rotation of the motor 43 in the opposite direction to raise the bed or the head or knee sections of the spring. it will be appreciated that manual release of the control member actuated to rotate either the head arm 64 or the knee arm 77 will permit automatic return by the spring 93 of all of the parts so manually actuated, the previously moved follower 92 being actuated by the spring to reposition the actuated function selector arm in neutral position. This will relieve the switch arm 55 from the actuating pressure of the associated stud 99 to permit the switch operating member 53 or 54 previously moved by the switch arm to return to normal inoperative position to deenergize the motor 43.

The same neutralizing positioning of the control unit 56 is effected in response to return of the Hi-Lo function control arm 86 to normal position by the nurse or other operator manually moving the Hi-Lo control member 88 back to its normal central or inoperative position. However, a NO-WAIT" arrangement is provided to save the time of the nurse or other attendant when it is desired to raise or lower the bed to its uppermost or lowermost position which comprises means for retaining the l-Ii-Lo control member 88 and the members manually movable thereby in operatedposition upon manual release of the control member after it has been moved to initiate raising or lowering of the bed. This NO-WAIT" means comprises a vertically disposed stationary plate 102 (FIGS. 2-4) having an inwardly extending horizontal flange at its upper margin which is secured, as by means of screws 103, to the supporting member 58. Slidably maintained on the vertical portion of the stationary plate 102 and supported thereby by means of guide studs 104 (FIG. 3) extending through horizontal slots 105 in the stationary plate 102 is a movable plate 106 having an outwardly extending horizontal flange at its upper end with an aperture 107 (FIG. 2) through which the switch plate engaging stud 91 depending from the Hi-Lo arm 86 extends. It will benoted that this horizontal flange on the movable plate 106 is disposed below the main body portion of the switch bar 55. As best seen in FIG. 3, the cooperating plates 102, 106 are provided with normally coinciding longitudinal slots 108 within which is maintained in any suitable manner a centering coil spring 109. This spring 109 functions to resiliently retain and return the movable plate 106 in and to its normal neutral position which, through the agency of theaperture 107 and stud 91 cooperating therewith, functions similarly to return the Hi-Lo selector arm 86 to normal neutral position and to resiliently retain it therein.

Detent means are provided for retaining the movable plate 106 in either position to which it is moved in response to operation of the Hi-Lo control member 88, either to the left or right of its normal neutral position of FIG. 3, to maintain the Hi-Lo function arm 86 and the parts moved thereby in such actuated positions upon manual release of the control member 88 after it has been selectively operated to initiate raising or lowering of the bed. This detent means comprises a ball 111 disposed in a suitable dimple in a leaf spring 112 secured to the outer surface of the movable plate 106 and urged inwardly thereby, and detent ball-receiving apertures 113 spaced longitudinally from each other in the stationary plate 102. Consequently, in response to movement of the plate 106 in either direction by the stud 91 which moves the switch bar 55 to energize the motor during the final increment of such movement, the ball 111 will be aligned with one or the other of the apertures 113 and moved by the spring 112 into latching engagement therein to frictionally retain the movable plate 106 in such actuated position. It will be appreciated, of course, that such movement of the plate 106 is not effected in response to operative move ment of either of the studs 99 by their function control arms 64 or 77 since, as shown in FIG. 2, the horizontal flange of the member 106 which contains the stud-em gaging aperture 107 terminates sufficiently short of the studs 99 as not to be engaged thereby.

Means are provided for automatically unlatching the above-described NO-WAIT" mechanism and effecting return to normal neutral position of the Hi-Lo control member 88 and the parts manually moved thereby during a selective operation thereof when the bed reaches its uppermost or lowermost position. This means comprises an inwardly extending flange 114 at each end of the movable plate 106 (FIGS. 2 and 4) adapted to be contacted and moved by a member 115 carried by the traveling nut which ismounted on the Iii-Lo screw 26 as the bed reaches either of such lowermost or uppermost positions. At that time, the movable plate 106 thereby is released from the latching engagement of the detent ball 111 in one or the other of the apertures 113 which permits the spring 109 to return the movable plate 106 to central or neutral position, along with the stud 91 engaged thereby and the Hi-Lo selector arm 86. This also returns the I-Ii-Lo control member 88 to normal intermediate position and moves the switch bar 55 from its active position to deenergize the motor 43.

Lockout means are provided of extremely simple construction for preventing operation of either the head or knee function selector controls which comprise selectively operable levers 116 (FIG. 5) associated, respectively, with the head control member 66 and the knee control member 79. Each lockout lever 116 is pivotally mounted at 117 on a suitable vertical frame plate 118 with a manually operable outer end extending through a slot 119 in the foot end cover plate 69. Each lever 116 is provided with a slot 121 in its upper edge vertically aligned with the :inner arm of the associated bell crank control member 66 or 79. A suitable toggle spring 122 is anchored at its outer end to the frame plate 118 at a point horizontally aligned with the pivot 117 and at its inner end to the lever 116 at a point disposed above the pivot 117 and the inner end of the spring when the lever.is in its upper latching position, which point of attachment of the inner end of spring 122 to the lever 116 will be disposed below the pivot 117 when the outer end of the lever is raised to disengage it from its associated control member 66 or 69. With this simple arrangement, each spring 122 resiliently maintains its associated lockout lever 116 in normal inoperative position and also retains the lever in operative position when the same is moved thereto. In that operative position, the slot 121 engages the. inner arm of the operating member 66 or 79 associated therewith to prevent movement of that operating member from its neutral position. By virtue of the previously described interconnection of the duplicate head and knee control members 71 and with their respective foot end head and knee control members 66 and 79, operation of the former also is prevented when the associated lockout lever 116 is moved to operative position.

Novel and simplified means are provided for disposing the bed frame in Trendelenberg position which, as best seen in FIGS. 5 and 6, comprises normally ineffective restraining means in the form. of a latch plate 123 pivotally mounted on the axle of each of the guide sheaves 31 (FIG. 6) which is supported at the foot end of the frame 1 1. Each latch plate 123 is connected at its inner end to a coil spring 124 to urge the outer end of the latch plate downwardly to its dotted line position of FIG. 6. This is the normal inoperative position of the latch plates wherein the nose or outer end of each is spaced inwardly from the associated inner leg 13, the outer leg 12 being recessed to accommodate the outer end of the latch plate, the guide sheave 31 and the cable 28. Adjacent its upper end, each inner leg 13 is provided with a slot 125 (FIG. 6) into which the inner end of the latch plate 123 may be projected when that end of the bed has been raised to its uppermost position, as shown in full lines in FIG. 6.

The inner portion of each latch plate 123 is provided with a notch 126 for engagement witn an outwardly extending end portion of a transverse rod 127. As shown in FIG. 5, one of these end portions of the rod 127 continues outwardly through a suitable slot 128 in the end cover plate 69 and terminates in a handle portion 129, the laterally extending main part of the rod 127 being suitably journaled on the bed frame. Consequently, after the bed has been raised to its uppermost position, depression of the handle portion 129 of rod 127 will pivotally move the latch plates 123 from their brokenline inoperative position of FIG. 6 to their full-line operative position to project the outer noses of the latch plates into the associated slots 125 in the inner legs 13. Subsequent operation of the I-Ii-Lo control member 88 to effect lowering of the bed will first bring the latch plates 123 downwardly into their full-line positions of FIGS. and 6 into engagement with the lower edge of the slots 125 to prevent further lowering of that end of the bed. It will be appreciated. that such downward movement of the inner end portions of the latch plates 123 is limited by engagement thereof with the upper surface of the lower end rail of the bed frame. Continued downward operation of the Hi-Lo mechanism will result in the other end of the bed being lowered into its lowermost position where it will be stopped automatically and the Hi-Lo control member 88 and the parts manually operated thereby returned to neutral position in a manner hereinbefore described. Subsequent movement of the Hi-Lo control member 88 to initiate raising of the bed and manual release thereof will result in the bed being returned to its uppermost position, wherein it will be stopped automatically in the manner previously noted. The springs 124 function during the terminal portion of such bed raising movement, after the outer ends of the latch plates 123 have been lifted thereby from engagement with the lower ends of the slots 125, to return the latch plates 123 and their rod 127, 129 automatically to normal inoperative position. It will be appreciated that this means comprising the normal inoperative latch plates I23 and their associated mechanism may be duplicated, if desired, at the head end of the bed for use in similarly functioning to effect the positioning of the frame in reverse Trendelenberg.

It is thought that the invention and many of the attendant advantages will be understood from the foregoing description, and it will be apparent that various changes may be made in the form, construction, and arrangement of the parts without departing from the spirit and scope of the invention or sacrificing all of its material advantages, the form hereinbefore described being merely a preferred embodiment thereof.

I claim:

1. In an electric hospital bed having an articulated spring with separately operable head and knee sections, independently operable actuating means for raising and lowering said spring and said head and knee sections, and a reversible motor for operating said actuating means to effect Hi-Lo, head or knee section functions; transmission means interposed between said motor and said actuating means selectively positionable to determine Hi-Lo, head or knee functions, switch means normally in neutral position and movable in either of two directions therefrom to cause energization of said motor for forward or reverse operation, a normally neutral control unit, and a control member for each of said Hi-Lo, head and knee functions selectively operable manually in either of two directions first to position said transmission means to determine the selected function and thereafter to move said switch means in a corresponding direction to effect the selected raising or lowering of said spring or said head section or said knee section.

2. An electric hospital bed according to claim 1, wherein said control unit comprises a selector movable to one of three positions to selectively position said transmission means, and three pivotally mounted function selector arms each operable by one of said manually operable control members to move said selector to the proper position regardless of which direction of movement has been imparted to the selectively operated control member.

3. An electric hospital bed according to claim 2, wherein said gear selector comprises a shuttle plate slidable to one of three positions.

4. An electric hospital bed according to claim 3, wherein each said function selector arm is engageable with said shuttle plate at two points spaced equidistantly from its pivot.

5. An electric bed according to claim 3, wherein one of said three positions of said shuttle plate comprises a neutral position, and spring means constraining said plate to said neutral position. i

6. In an electric bed according to claim 1, wherein said control members have normal neutral positions, means for automatically returning a manually operated said head or knee function control member to neutral position upon manual release thereof.

7. An electric bed according to claim 2, wherein the final portion'of manual movement of any one of said function selector arms actuates said switch means.

8. In an electric bed according to claim 6, latching means operable in response to movement of said Hi-Lo control member for retaining the same, said switch means and said control unit in operative positions upon manual release of said I-Ii-Lo control member.

9. In an electric bed according to claim 8, means automatically operable when said bed reaches its uppermost or lowermost position to render said latching means ineffective and thereby effect return of said Hi- Lo control member, said control unit and said switch means to neutral positions.

10. An electric bed according to claim 9, wherein said latching means comprises a stationary plate, a movable plate slidably mounted on said stationary plate for limited movement by said Hi-Lo control member, and normally ineffective resilient detent means rendered effective upon sliding of said movable plate in either direction in response to operation of said l-Ii-Lo control member.

11. In an electric bed according to claim 10, a spring cooperating with said stationary and movable plates to resiliently maintain the latter in a normal central position.

12. In an electric bed according to claim 6, wherein said control members are disposed adjacent the foot end of the bed, duplicate head and knee control members located for convenient operation by a patient on the bed and interconnected, respectively, with said head and knee control members at the foot of the bed,

and lockout means disposed adjacent the latter and selectively operable to render inoperative the associated said head and knee control and duplicate control members.

13. A hospital bed according to claim 12, wherein each said lockout means comprises a normally inoperative pivotally mounted lever having an edge notch engageable with the associated said control member in response to movement to operative position.

14. In an electric bed according to claim 9, normally ineffective Trendelenberg restraining means mounted at one end of said bed, control means selectively operable to render said restraining means effective upon rais- 

1. In an electric hospital bed having an articulated spring with separately operable head and knee sections, independently operable actuating means for raising and lowering said spring and said head and knee sections, and a reversible motor for operating said actuating means to effect Hi-Lo, head or knee section functions; transmission means interposed between said motor and said actuating means selectively positionable to determine Hi-Lo, head or knee functions, switch means normally in neutral position and movable in either of two directions therefrom to cause energization of said motor for forward or reverse operation, a normally neutral control unit, and a control member for each of said Hi-Lo, head and knee functions selectively operable manually in either of two directions first to position said transmission means to determine the selected function and thereafter to move said switch means in a corresponding direction to effect the selected raising or lowering of said spring or said head section or said knee section.
 2. An electric hospital bed according to claim 1, wherein said control unit comprises a selector movable to one of three positions to selectively position said transmission means, and three pivotally mounted function selector arms each operable by one of said manually operable control members to move Said selector to the proper position regardless of which direction of movement has been imparted to the selectively operated control member.
 3. An electric hospital bed according to claim 2, wherein said gear selector comprises a shuttle plate slidable to one of three positions.
 4. An electric hospital bed according to claim 3, wherein each said function selector arm is engageable with said shuttle plate at two points spaced equidistantly from its pivot.
 5. An electric bed according to claim 3, wherein one of said three positions of said shuttle plate comprises a neutral position, and spring means constraining said plate to said neutral position.
 6. In an electric bed according to claim 1, wherein said control members have normal neutral positions, means for automatically returning a manually operated said head or knee function control member to neutral position upon manual release thereof.
 7. An electric bed according to claim 2, wherein the final portion of manual movement of any one of said function selector arms actuates said switch means.
 8. In an electric bed according to claim 6, latching means operable in response to movement of said Hi-Lo control member for retaining the same, said switch means and said control unit in operative positions upon manual release of said Hi-Lo control member.
 9. In an electric bed according to claim 8, means automatically operable when said bed reaches its uppermost or lowermost position to render said latching means ineffective and thereby effect return of said Hi-Lo control member, said control unit and said switch means to neutral positions.
 10. An electric bed according to claim 9, wherein said latching means comprises a stationary plate, a movable plate slidably mounted on said stationary plate for limited movement by said Hi-Lo control member, and normally ineffective resilient detent means rendered effective upon sliding of said movable plate in either direction in response to operation of said Hi-Lo control member.
 11. In an electric bed according to claim 10, a spring cooperating with said stationary and movable plates to resiliently maintain the latter in a normal central position.
 12. In an electric bed according to claim 6, wherein said control members are disposed adjacent the foot end of the bed, duplicate head and knee control members located for convenient operation by a patient on the bed and interconnected, respectively, with said head and knee control members at the foot of the bed, and lockout means disposed adjacent the latter and selectively operable to render inoperative the associated said head and knee control and duplicate control members.
 13. A hospital bed according to claim 12, wherein each said lockout means comprises a normally inoperative pivotally mounted lever having an edge notch engageable with the associated said control member in response to movement to operative position.
 14. In an electric bed according to claim 9, normally ineffective Trendelenberg restraining means mounted at one end of said bed, control means selectively operable to render said restraining means effective upon raising of said bed to its uppermost position, whereby subsequent operation of said Hi-Lo control member to effect downward movement of said bed and manual release thereof will result in downward movement of the opposite end of said bed and automatic stopping thereof in its lowermost position, and means operable automatically to return said restraining means to ineffective position upon subsequent raising of said bed to uppermost position in response to operation of said Hi-Lo control member to effect upward movement of said bed and manual release thereof. 